BILBAO, Spain, May 1 (Reuters) - Three first-half goals helped Manchester United ( MANU ) put themselves on the cusp of the Europa League final on Thursday, with the Premier League side earning a 3-0 semi-final first leg win away at Athletic Bilbao.

In a raucous San Memes atmosphere, with supporters dreaming of a first-ever European trophy, veteran midfielder Casemiro arrived at the back post to give the visitors the lead 30 minutes in.

United, who are having a miserable season domestically, were given another boost five minutes later as Bilbao defender Daniel Vivian was sent off for fouling Rasmus Hojlund in the penalty area and Bruno Fernandes converted the resulting spot kick.

The United fans high in the top tier were in dreamland moments later as captain Fernandes raced through to put the seal on a victory, and perhaps even the tie, before the interval.

Bilbao, who have the added incentive that the final will be hosted at their own stadium on May 21, could not muster a response in the second half with depleted numbers, leaving United to coast to the most unlikely first-leg success.